The present invention relates to a cutting device for cutting the thread chain, tape or the like, which joins successive sewn parts, and particularly for cutting near each of the sewn parts with one cutting.
A cutting device for threads or for the thread chain of sewn parts being worked on sewing machines is known from Federal Republic of Germany Pat. No. 10 65 704. In this publication, a scissors is located below the resting surface of the sewn material. The scissors includes two blades which are swingable around a common fixed pivot point. The scissors is moved upward in the direction toward the sewing place and thereby cuts the thread chain. This cutting device has a disadvantage. If the thread chain is to be cut close to the adjacent edges of two neighboring pieces of sewn material, which edges extend transversely to the sewn seam, then two cuts are required. One cut is made close to the sewn material edge of one of the adjacent sewn material parts and the other close to the edge of the other parts. Only if the thread chain which connects the adjacent sewn parts has a short length, amounting to only a few millimeters, is a single cut sufficient. Dependable cutting of the thread chain is not possible if the adjacent edges of the sewn material, beyond which the thread chain has been sewn, do not extend practically at right angles to the direction of transport of the sewn material through the sewing machine. When there is a relatively short thread chain, the sewn parts overlap in the region of the said sewn material edges. The tips of the upwardly moving scissor blades press against the overlapped material and thereby shift them upward along with the thread chain. As a result, cutting of the thread chain is prevented. The known cutting device has a further disadvantage that the scissors and their actuating members are arranged below the place of sewing. In modern high-speed sewing machines, the region around the looper or loopers has scarcely any free space for the arrangement of other structural parts like the scissors and their actuating members.